One of the reasons I like researching in libraries is that you sometimes find things that you might not have known existed otherwise. While browsing the Logan Square branch of the Chicago Public Library this weekend, looking for books that covered Chicago during the 1970s and 1980s, among the usual suspects I saw a cheaply bound book in hideous late-'70s/early-'80s beige and brown, the spine reading SPLIT-SECOND DECISIONS.

Out of curiosity I pulled it off the shelf. The full title was Split-Second Decisions: Shootings of & by Chicago Police. (A shorter version is available online.) The author of the introduction was familiar: Norval Morris, a legendary criminologist and former University of Chicago law school dean. So I picked it up.

It turned out to be a thorough study of what people now refer to as "officer-involved shootings" and the shootings of officers by civilians from 1974 to 1978 in Chicago, perhaps the most thorough investigation of the subject at its time. Then as now—as a Washington Post team has learned in assembling its epic 2015-2016 nationwide database—the data was hard to get. It took 15 people almost three years to get it, although they note that "this 'paper chase' would have been unnecessary if access to police records could have been secured at the outset."

The catalyst for the report was the shooting of a white 18-year-old in Jefferson Park in June of 1977. John Neuman was breaking into a garage on West Sunnyside in order to, according to his father, retrieve a minibike from someone who hadn't fully paid him for it. Cops caught and handcuffed him; he ran; an officer fired a warning shot, which shattered on the pavement; a fragment hit Neuman in the back and penetrated his lung. Neuman died two hours later. "A pathologist said he either bled to death or suffocated in his own blood," the Tribune reported.

The officer, Philip Onesto, was subsequently fired, but the firing was reversed by an appellate court in 1980. The family sued the city, the officer, and the hospital who treated Neuman for almost $5 million; nine years later they settled for $875,000. What he'd done was technically legal under state law, which permitted the use of deadly force "to prevent the escape of a person believed to have committed a felony."

In Illinois, this was limited to "forcible" felonies, which included burglary. This, as the report notes, dated back to English common law in the days of hand-to-hand combat. When guns became prevalent, English law changed in the 19th century to reflect that "the circumstances in which it can be reasonable to kill another in the prevention of crime must be of an extreme kind; they could probably arise only in the case of an attack against a person which is likely to cause death or serious bodily injury and where killing the attacker is the only practicable means of preventing the harm. It cannot be reasonable to kill another merely to prevent a crime, which is directed only against property." America, including the state of Illinois, evolved towards similar standards much more slowly, primarily following the creation of the Model Penal Code in 1961. Until Tennessee v. Garner in 1985, the majority of states followed the common-law model.

(In Chicago, police directives still allow deadly force against a suspect fleeing a forcible felony, which includes burglary. A 2016 draft of updated guidelines has nixed that language, though it has not yet been implemented.)

Back to the '80s. With the law being pushed to evolve, and the death of Neuman fresh on the minds of the city, the Chicago Law Enforcement Study Group set out to unearth the data.

They found that, from 1974 through 1978, 2,876 civilians (about 575 per year) were fired at. Of those, 523 civilians were struck by police bullets, or about 105 per year, and 132 of them were killed, about 26 per year.

The raw numbers have dropped considerably over the years. In August last year, a team of Tribune reporters gathered similar data over a six-year period, from 2010 through 2015. They found that 528 people were fired at, or 88 per year; 262 were struck, or about 44 per year; and 92 were killed, or about 15 per year.

Some of this can, perhaps, be attributed to the fact that there are simply fewer people in Chicago now. In 1980, there were just over 3 million people; in 2010, a bit fewer than 2.7 million, or about a 10 percent decline.

More can probably be attributed to a general decline in crime. In 1976, the Chicago Police Department reported 214,468 crimes, for a rate of 63.5 per 1,000 people. In 2010, they reported 152,031, or about 56 per 1,000. (The number of officers reported to the FBI declined less: 13,076 in 1974 to 12,515 in 2010, about a seven-percent drop.)

The demographics, though, are eerily similar. Black people are disproportionately more likely to be shot by police than any other race group. From 1974 through 1978, 70 percent of those shot were black, 20 percent white, and 10 percent Hispanic; during that period—and this is a dramatic statistic in itself—the city's population shifted from 60 percent white, 33 percent black, and 7.5 percent Hispanic to 47 percent white, 41 percent black, and 12 percent Hispanic.

In 2010, Chicago was 32 percent black, 32 percent non-Hispanic white, and 28 percent Hispanic. In the Trib's six-year timeframe, 80 percent of those shot by police were black, 13 percent Hispanic, and five percent white. The Chicago Police Accountability task force, working with a dataset that covered 2008 to 2015, found that of the 404 people shot by police (51 per year), 74 percent were black, 14 percent Hispanic, and 8 percent white.

"CPD's own data gives validity to the widely held belief the police have no regard for the sanctity of life when it comes to people of color," the task-force report argued. The Chicago Law Enforcement Group came to a much more guarded conclusion after comparing shooting rates to arrest rates, and patterns of race in both shooters and those shot: "While our data are not adequate for drawing confident conclusions, our analysis does not reveal findings which, on balance, are consistent with the racism theory."

The Law Enforcement Group also looked at the Office of Professional Services, the predecessor to the Independent Police Review Authority, agencies charged with investigating complaints against the police. They found that seven percent of shooting cases led to adverse findings for the officer, though that total was inflated by rule violations, like the use of unauthorized ammunition, in otherwise-justified shootings—lending credence to a Tribune report that compared criticisms of OPS to IPRA and concluded that both had failed at holding police accountable.

Though they're just years-long snapshots in time, there seems to have been progress, though troublesome patterns remain. The number of people fired at appears to have dropped precipitously. The number hit by bullets has declined. It's declined as a percentage of population: from 3.5 per year per 100,000 people from 1974-1978 (using 1980 population totals) to 1.6 per year per 100,000 people from 2010-2015 (using 2010 population totals). It's declined as a percentage of index crimes: from 48 per 100,000 crimes to 33 per 100,000 crimes. Perhaps change is possible: even if it's slow, and even if we don't really understand why.